No software-based technique can fully replace bulk collection of communications data for electronic intelligence gathering, the U.S. National Research Council said in a report released on Thursday.

The report, however, said some methods could be developed to better target collection and control the use of the collected data, which could help protect privacy of the information and allay civil liberties concerns.

“From a technological standpoint, curtailing bulk data collection means analysts will be deprived of some information,” committee chairman Robert Sproull, former director of Oracle’s Sun Labs, said in the report.

“It does not necessarily mean that current bulk collection must continue," Sproull added.

The report suggested such approaches as automated systems for isolating collected data, restricting queries that can be made against those data and auditing the use of the data.

The council did not take a position on the merits of collecting the data but was asked to look for effective software alternatives to bulk collection.

It concluded there weren't any viable alternatives, in cases when, for example, the National Security Agency wants to examine records whose significance only becomes clear years later -- such as previous communications of new terror suspects.

'Set up to fail'

A draft of the study was sent to a variety of reviewers, including Fred Cate, a law professor and privacy expert at Indiana University, who criticized its approach in an email to The Associated Press.

“The study seemed set up to fail,” Cate told AP. “It imposes an impossibly high standard -- to find a technological tool that is even better than having access to bulk collection. It seemed clear from the outset that the answer is no.”

The program, conducted under Section 215 of the Patriot Act, collects the “to and from” information of most domestic landline calls, but not the content of the communications. Officials have said It does not gather most cellphone calls for logistical and other reasons, officials have said.

The study, commissioned last year in the wake of surveillance revelations by former NSA contractor Edward Snowden, was to assess the feasibility of creating software that would allow intelligence agencies to conduct targeted information gathering, rather than bulk collection of phone or email communications.

Arguably the most controversial example of bulk data collection is the NSA's gathering and storing of American calling records, a program kept secret for years and disclosed by Snowden.

The study was sponsored by the Office of the Director for National Intelligence. The study was conducted by a committee of the National Academies, which advises the government on scientific matters.